Due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake which occurred on March
11, 2011, TEPCO's facilities including our nuclear power stations have been
severely damaged. We deeply apologize for the anxiety and inconvenience
caused.
With regard to the accident at Fukushima Daiichi Nuclear Power Station, on
April 17, 2011, we have compiled the roadmap towards restoration from the
accident and on July 19 we accomplished the Step1 target "Radiation dose is
in steady decline". Then on December 16 we confirmed the accomplishment of
the Step 2 target "Release of radioactive materials is under control and
radiation doses are being significantly held down".
In addition, on December 21, 2011, we have compiled the "Mid-to-long-Term
Roadmap toward the Decommissioning of Fukushima Daiichi Nuclear Power Units
1-4, TEPCO".
In addition to the maintenance of the plant's stable condition, we will
implement Mid-to-Long Term countermeasures towards the decommissioning of
Fukushima Daiichi Nuclear Power Units 1-4 to enable evacuees to return to
their homes as soon as possible and reduce the anxiety of the people in
Fukushima and the whole nation as soon as possible.
Below is the status of TEPCO's major facilities.
* The updates are underlined.
[Nuclear Power Station]
· Fukushima Daiichi Nuclear Power Station: Unit 1 to 3: shut down due to
the earthquake:
(Units 4 to 6: outage due to regular inspections before the earthquake)
- With regard to the water injection volume for Unit 2 reactor, which was
increased with temperature figure raising, we have gradually adjusted it
to the original volume before temperature increasing (Feed water system:
approx. 3.0m3/h, core spray system: approx. 6.0m3/h). During our
observing the plant parameter after the decreasing the flow rate of feed
water system on February 22, we found that one thermometer in the lower
part of the RPV indicated the different movement from others. From 0:21
pm to 2:48 pm on February 23, we investigated the concerned device. As
the result of the measurement of DC resistance, we found no breaking wire
and availability of the thermometer. But we confirmed that the DC
resistance of it became higher than the previous measurement test data.
We will evaluate the soundness of the concerned device and examine
correspondence in future. We make sure no re-criticality state because
there were no significant changes at the monitoring post and as the
result of the sampling for the Gas Control System of the Unit 2, we
confirmed that the concentration of Xe-135 was below the detectible
limit.
· At 11:00 am on February 26, the temperature of the lower part of the RPV
(top of the lower head 135° ) : approx. 44.7 °C
(Reference)
· At 11:00 am on February 26, the temperature of the lower part of the RPV
(top of the lower head 270° ) : approx. 40.5 °C
- At 8:30 am on February 25, TEPCO and partner company workers found a
water leakage at the welded piping part at B line of the 2nd Cesium
adsorption apparatus (SARRY) installed on the 1st floor of the
Centralized Waste Treatment Facility [Miscellaneous Solid Waste Volume
Reduction Treatment Building [High Temperature Incinerator Building]).
The leakage volume was just one drop per second and the total amount of
water leaked was approx. 10 litters, staying within the barrier of the
building and not leaking out. At 10:44 am on the same day, we stopped
operation of the 2nd Cesium adsorption apparatus and closed a valve
positioned in the upstream of the leaked point to prevent the water from
further leaking, and at 11:10 am on the same day, we confirmed stoppage
of the water leakage. When measuring the surface radiation rate, it was
approx. 4-5mSv/h (2mSv/h in the background). As the accumulated water
treatment will not be affected despite the suspension of the apparatus
and sufficient purified water remains, there is no effect on reactor
water injection into. The nuclide analysis results for the water leakage
were as follows:
I-131: Below detection limit, Cs-134: 1.3 x 105 Bq/cm3, Cs-137: 1.8 x
105 Bq/cm3
After that, per the remote controlling implementation of the 2nd Cesium
absorption apparatus (B line), where a water leakage was found, we have
activated the system A line since 6:41 pm. At 6:44 pm, the water flow
amount reached 20 m3/h and we stably started treating the accumulated
water. At 8:35 am on February 26, to replace the duct and filter of the
apparatus B line, we shutdown A line of the apparatus. Since the repair
work was finished thereafter, at 1:31 pm on the same day, both A and B
lines of the apparatus activated, and at 1:50 pm, it reached regular flow
amount (33.6 m3/h), enabling to start a stable treatment of the
accumulated water.
- At 2:04 pm on February 23, from the Unit 2 Turbine Building basement
towards the Centralized Waste Treatment Facility (Process Main Building),
transfer of the accumulated water started. At 1:51 on February 26, the
transfer stopped.
- At 2:04 pm on February 26, from the Unit 2 Turbine Building basement
towards the Centralized Waste Treatment Facility [Miscellaneous Solid
Waste Volume Reduction Treatment Building [High Temperature Incinerator
Building]), transfer of the accumulated water started.
· Fukushima Daini Nuclear Power Station:
Units 1 to 4: shutdown due to the earthquake
· Kashiwazaki Kariwa Nuclear Power Station:
Units 6: under normal operation
(Units 1 to 5 and 7: outage due to regular inspections)
[Thermal Power Station]
· Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Hydro Power Station]
· Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Transmission Facilities]
· Power supply has returned to normal and the facilities damaged by the
earthquake are now being handled in a timely manner.
[Impacts on Power Supply and Demand Balance]
This winter, there are some minus factors such as the regular inspection of
Unit 5 at Kashiwazaki-Kariwa Nuclear Power Station. On the other hand,
there are several plus factors such as the recovery of the common thermal
power stations which suffered the earthquake. As a result, we expect to
secure 53.7 GW (at the end of February) supply power.
Compared to the maximum demand in the last winter, which is 51.5 GW, we
will have 2.2 GW generation reserve margin.
We expect to maintain stable power supply this winter. However, as there
remains possibilities of unplanned shutdowns at our power stations and
growth in the demand according to the rapid change in the temperature, we
would like to ask your reasonable effort to save electricity.
We will continue to make our efforts to maintain stable operation and
maintenance of the power facilities in order to "prevent in principle" the
planned blackouts and secure power supply.
Appendix: Past Progress (As of 3:00 pm on February 26, 2012) (PDF 455KB)
Appendix: Past Progress (From March 11, 2011 to July 31, 2011) (PDF 225KB)
* Revised past progress